PURPOSE: To obtain the titled large-particle diameter copolymer at a low energy consumption, by copolymerizing formaldehyde with a cyclic ether in the presence of an oxymethylene polymer and a catalyst comprising a metal chelate compound and a Lewis acid.
CONSTITUTION: An oxymethylene copolymer is obtained by copolymerizing formaldehyde (preferably, of a water content of below 0.1wt%) with a cyclic ether of formula I or II (wherein R1W4 are each H, alkyl, aryl or cycloalkyl, m is 1W3, and n is 2W6), e.g., ethylene oxide, in the presence of an oxymethylene copolymer containing no or below 50wt% inert organic solvent and in the presence of a catalyst comprising a metal chelate and a Lewis acid. The above catalyst must have a molar ratio of the metal chelate to the Lewis acid of at least 5× 10-4, preferably 5×10-3.
| JPS5487794 | PREPARATION OF POLYOXYMETHYLENE |
| WO/2005/032597 | BIODEGRADABLE POLYACETALS FOR IN VIVO POLYNUCLEOTIDE DELIVERY |
HISATOMI KATSUKI
KAWAMURA SHIGERU
| JPS483558A |